While there are many instances where there is a one-to-one correspondence between RDA and MARC 21, there are cases where the level of granularity in the MARC 21 element set and RDA element set differs. Where a single RDA element is equivalent to more than one MARC 21 element, all applicable MARC 21 elements are provided. Where the content of the RDA element would be recorded in an uncontrolled form no mapping has been made to controlled vocabularies in MARC. This may change!

The table includes a detailed mapping of Appendix J, Relationship designators: relationships between works expressions, manifestations, and items. Mappings have been provided for each of the prescribed methods of representing relationships:

006/16 and 008/33 indicate the script of the title for Continuing resources (used by ISSN Centres, at present). 008/35-37 and 041 indicate the language of the resource. MARC does not provide coded data for scripts.

* Field 580 can be used wherever a linking entry is insufficient to express the nature of the relationship. * Although there is no corresponding relationship designator defined in Appendix J, field 786 can be used to record a related work with the nature of the relationship indicated in subfield $i Relationship information. * Field 787 can be used to express any of the linking entry relationships outlined below as well as any of the relationships flagged as N/A at identifier and structured levels.

* Although there is no corresponding relationship designator defined in Appendix J, field 786 can be used to record a related work with the nature of the relationship indicated in subfield $i Relationship information. * Field 787 can be used to express any of the linking entry relationships outlined below as well as any of the relationships flagged as N/A at identifier and structured levels.

* Although there is no corresponding relationship designator defined in Appendix J, field 786 can be used to record a related work with the nature of the relationship indicated in subfield $i Relationship information. * Field 787 can be used to express any of the linking entry relationships outlined below as well as any of the relationships flagged as N/A at identifier and structured levels.